It is known to circulate the cooling water of an internal combustion engine by means of a pump that is located in the circulation system between the engine and the radiator and is driven by way of a V-belt or an electric motor. The radiator has a fan that is driven by the engine or by an electric motor. The devices required for cooling the engine must be individually attached as separate components and require a considerable amount of space in the engine compartment of a motor vehicle.
A thermostat valve is located in the cooling circulation system and is connected so that, after the startup of the internal combustion engine, the valve does not at first permit the cooling water to flow through the radiator until it is sufficiently warm. Thus the engine reaches the required operating temperature earlier.
It is furthermore known to dispose a latent heat accumulator in the cooling circulation system, which heat accumulator stores heat during the operation of the motor vehicle and retains this heat for a long time even after the motor vehicle is turned off. If the cold engine is started up, then the cooling water and the engine are immediately heated up by the latent heat accumulator, so that the emissions in a cold start are considerably reduced and the heating system is effective earlier. It is also known to locate an auxiliary heating device in the cooling circulation system, which device heats the engine and the passenger compartment before the startup.
The pump located in the cooling circulation system is not driven before the internal combustion engine is started up, so that the latent heat accumulator or the auxiliary heating device does not heat the water of the cooling circulation system. As a result, the engine only receives heated cooling water after it has been started up, so that at the beginning, it produces considerable emissions (in particular CO.sub.2).